bus: mhi: core: Add support for processing events from client device

This commit adds support for processing the MHI data and control
events from the client device. The client device can report various
events such as EE events, state change events by interrupting the
host through IRQ and adding events to the event rings allocated by
the host during initialization.

This is based on the patch submitted by Sujeev Dias:
https://lkml.org/lkml/2018/7/9/988Signed-off-by: Sujeev Dias <sdias@codeaurora.org>
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
[mani: splitted the data transfer patch and cleaned up for upstream]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Tested-by: Jeffrey Hugo <jhugo@codeaurora.org>
Link: https://lore.kernel.org/r/20200220095854.4804-11-manivannan.sadhasivam@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/bus/mhi/core/init.c

@@ -543,6 +543,18 @@ static int parse_ev_cfg(struct mhi_controller *mhi_cntrl,
 
 		mhi_event->data_type = event_cfg->data_type;
 
+		switch (mhi_event->data_type) {
+		case MHI_ER_DATA:
+			mhi_event->process_event = mhi_process_data_event_ring;
+			break;
+		case MHI_ER_CTRL:
+			mhi_event->process_event = mhi_process_ctrl_ev_ring;
+			break;
+		default:
+			dev_err(dev, "Event Ring type not supported\n");
+			goto error_ev_cfg;
+		}
+
 		mhi_event->hw_ring = event_cfg->hardware_event;
 		if (mhi_event->hw_ring)
 			mhi_cntrl->hw_ev_rings++;
@@ -772,6 +784,12 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 
 		mhi_event->mhi_cntrl = mhi_cntrl;
 		spin_lock_init(&mhi_event->lock);
+		if (mhi_event->data_type == MHI_ER_CTRL)
+			tasklet_init(&mhi_event->task, mhi_ctrl_ev_task,
+				     (ulong)mhi_event);
+		else
+			tasklet_init(&mhi_event->task, mhi_ev_task,
+				     (ulong)mhi_event);
 	}
 
 	mhi_chan = mhi_cntrl->mhi_chan;

drivers/bus/mhi/core/internal.h

@@ -500,6 +500,8 @@ struct mhi_buf_info {
 	dma_addr_t p_addr;
 	size_t len;
 	enum dma_data_direction dir;
+	bool used; /* Indicates whether the buffer is used or not */
+	bool pre_mapped; /* Already pre-mapped by client */
 };
 
 struct mhi_event {
@@ -637,6 +639,14 @@ static inline void mhi_free_coherent(struct mhi_controller *mhi_cntrl,
 	dma_free_coherent(mhi_cntrl->cntrl_dev, size, vaddr, dma_handle);
 }
 
+/* Event processing methods */
+void mhi_ctrl_ev_task(unsigned long data);
+void mhi_ev_task(unsigned long data);
+int mhi_process_data_event_ring(struct mhi_controller *mhi_cntrl,
+				struct mhi_event *mhi_event, u32 event_quota);
+int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl,
+			     struct mhi_event *mhi_event, u32 event_quota);
+
 /* ISR handlers */
 irqreturn_t mhi_irq_handler(int irq_number, void *dev);
 irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *dev);

include/linux/mhi.h

@@ -31,6 +31,7 @@ struct mhi_buf_info;
  * @MHI_CB_EE_MISSION_MODE: MHI device entered Mission Mode exec env
  * @MHI_CB_SYS_ERROR: MHI device entered error state (may recover)
  * @MHI_CB_FATAL_ERROR: MHI device entered fatal error state
+ * @MHI_CB_BW_REQ: Received a bandwidth switch request from device
  */
 enum mhi_callback {
 	MHI_CB_IDLE,
@@ -41,6 +42,7 @@ enum mhi_callback {
 	MHI_CB_EE_MISSION_MODE,
 	MHI_CB_SYS_ERROR,
 	MHI_CB_FATAL_ERROR,
+	MHI_CB_BW_REQ,
 };
 
 /**
@@ -92,6 +94,16 @@ struct image_info {
 	u32 entries;
 };
 
+/**
+ * struct mhi_link_info - BW requirement
+ * target_link_speed - Link speed as defined by TLS bits in LinkControl reg
+ * target_link_width - Link width as defined by NLW bits in LinkStatus reg
+ */
+struct mhi_link_info {
+	unsigned int target_link_speed;
+	unsigned int target_link_width;
+};
+
 /**
  * enum mhi_ee_type - Execution environment types
  * @MHI_EE_PBL: Primary Bootloader
@@ -312,6 +324,7 @@ struct mhi_controller_config {
  * @transition_list: List of MHI state transitions
  * @transition_lock: Lock for protecting MHI state transition list
  * @wlock: Lock for protecting device wakeup
+ * @mhi_link_info: Device bandwidth info
  * @st_worker: State transition worker
  * @fw_worker: Firmware download worker
  * @syserr_worker: System error worker
@@ -376,6 +389,7 @@ struct mhi_controller {
 	struct list_head transition_list;
 	spinlock_t transition_lock;
 	spinlock_t wlock;
+	struct mhi_link_info mhi_link_info;
 	struct work_struct st_worker;
 	struct work_struct fw_worker;
 	struct work_struct syserr_worker;